The invention relates to devices for heating components such as valves, fittings, or other items related to controlling fluid flow.
Many industrial and commercial processes use compressed gas supplied from a reservoir, such as a tank or gas cylinder. The flow of gas from the reservoir, for example, a cylinder, is controlled by a valve, usually mounted directly on the cylinder. When a compressed gas is permitted to expand freely through a throttling device such as a valve, it undergoes the Joule-Thomson effect, a process by which the gas temperature increases or decreases during free expansion at constant enthalpy (no work extracted from the gas, no heat transfer to or from the gas). For most gases used in industrial applications, the conditions of pressure and temperature are such that the Joule-Thomson effect causes the gas to cool as it is released from the cylinder. The cooling can be significant and cause the moving parts of the valve to contract and jam, rendering the valve inoperable. Furthermore, moisture in the air within and surrounding the valve may condense and freeze within and/or on the valve, also rendering it inoperable. Any moisture in the gas will also condense in the valve passageways, accumulate, and choke off the flow of gas from the valve. There is clearly a need for a device that can prevent the malfunctioning of valves or other fluid flow devices due to overcooling upon free expansion of gas from a reservoir.